Regeneration of waste rubber



Aug. 20, 1946. JOHNSTON REGENERATION QF WASTE RUBBER 5 Shets-Sheet 1 E L U E TI Original Filed Nov. 12, 1942 d mg 5 Sheets-Sheet 2 A. JOHNSTON REGENERATION OF WASTE RUBBER Original. Filed Nov. 12, 1942 Aug. 20, 1946.- ON 2,406,297

REGENERATION 0E ASTE RUBBER Original F iled Now l2, 1942 5 Sheets-Sheet s Aug. 20, 1946.

1 Original Filed Nov. 12, 1942 A. JOHNSTON 2,406,297

REGENERATION OF WASTE RUBBER S-Sheets-Sheet 4' Aug. 20, 1946. v A! JOHNSTON 7 2,406,297

' REGENERATIPN o'F WASTE RUBBER Original Filed Npv. 12, 1942 SSheetS-Sheet 5 4 48 F154 Fig.5.

Ly Even 2 Patented Aug. 20, 1946 REG NERA I N ,o twesri' Missi e.

Alexander-Johnston; Edinburgh; Scotland,- asr H signor to The-North British Rubber Company Limitedy'Edinbiirgh, sc t 'a I o riginali application Novemhen; Serial v. 'No. 465,400. Divided and-this.applicationJanuary 7,'1944; Serial N0.

ainMar ch 3,1942

8. Claims.

This;inventionfrelates-to' the regeneration or 're'claimingofyulcanised waste rubber and/ or Vuleesisee waste rubber containing fibrous material,

so'jthat it may be re-used for manufactu'ring go'ods or articles. 1

V In my o-pending application SerialNo. 465,400, froni which the presentappncation is divided out, I *hav described aprocess' for regenerating or reclaiming was'te'rubber, which involves the-use of flueor exhaust gas for such'a purpose; and the object or the present invention-is anapparatus iby whichthe use and the effct of such gases is wefl'efotive;ljy-realised.-'

A furtherfobjeotof theinvention is to so carry onthe operation that thereis' no danger of fire e g-tnef treatment." p I i i F 'e'nee wninew 'be made to-thiaacdompanying drawings which illustrate by way of example we "termsof apparatus by .iw'hi' be Carried into jefie'clt; gqr'es' 1 and 1--sho'w in-'two ifa'tion partly in section of a tunnelappara'tus through-{which flue gas is passed in 'c'ountercurrent to' the-Das'sage of' the waste rubberto be the invention "treated" r v jF igures2and'2 constitute a plan view in two portions similar to-Figu'r'e -1. ::3.:F *igur :3 is ariiend'felevation :of Figure 1', and Eig-ur'e4showsaperspective 'vie w o'f a form of op'en me'sh container hereinafter referred to. l V Figure I 5: is a detail= section: taken on the .line

6 S'6,'Figur 4,'and a i #aFigure' 6- is a" diagrammatic plan view oi. the plantirwith" a modified lu'n'lo'ading and reloading system. 1. Referring: to Figures '1 and1 ;"2o,and.2 tand the apparatus comprisesa tunnelJ lloibri'ckwork or other refractory material and. the. top "of the tunnel. may beior'med'by a 'series of 1 concrete slabs 'l l which may be reinforced in the. usual way; and may each be adaptedv for removal -as will hereinafter a'ppearjach :bein'g: fitted. with an inspection opening 12 closed by altrlansparent or other. suitableaplatere'lt ."Toward's; one end of the tunnel.,an=.inlet=l"4 is provided in the top by: which a portion iofi'the; :ordin'arymfiue vgases lpassingiaway toa factoryzchimney through a flue indicated atsl 5; is divertedsth'rough anielbowxduct l6, controlled bydamper,",andwdrawnintO a casing J8 in :which a-i1fan.;;(notshown): delivers the flue gases throughfltheinlet, !4 into the tun- 'n -t ,Theimetllist-pre erab y also provided with ;.1dem r 9 m unted 1; as a tqfi ..Whi a be externally controlled by a cross ghandlej. 2|. The; vfa i driyenl y an: .e1eQtriegmoto1: :or; other (cilia-f2) prime mover 22, through a belt drive 23 and .fan

"shaft 24", but any other drive may be used.

The' fiue gases'forced into the tunnel, travel therethrough towards its left-hand .e'nd where 'theyfare carried away by the draught of, and

through an'elbow duct 25 back'to; the main line l5'o'r hthe'rWisIuhder the control of a damperZB 'inountedon shaftZTi'and operated externally by a lever' 28 which is adjusted relatively to a fixed {quadrant 29-or many other suitable'wayv It is not necessary to use-the whole of the flue gases 1 since a portion-only thereof may be divertedjior the purposes of this invention. a

f --The plant is" preferably so designed that the :15 -'regula-tion of*-the tunnel temperature may be,

controlled "by the 'variation of g the fan draught; by the r'e-circulationa of 'the' l-used flue gases; by the 'admi'ssion' of cooled flue 'gasesi after passing "through the usual hea't 'economiser or. by .other {suitable means; or by the admission of heated gasesfroin any suitable: source. :The .temperafture is preferably controlled thermostatically by any suitable means. I

-For these andother purposes various recording irist'ruments are arranged :in a:casingi don the tunnelas-"shown by Way of example in Figure 1. 'Thus'b-indicates a manometer gauge which is in communication by a duct 0 with the main flue5--passing .tothe chimney. d is a temperaturerecorder; e is-a clock'to timeIthe various 'step's'in'the process and f is a manometer which is in communication by the duct 9 with the outlet:duct--25.-

- 'Ihe-composition of .the gas may be controlled or varied-by the admission of air on the one hand,

or- 'byfnitrogen, carbon dioxide or. other inert gason the other hand,iby means of special inlets in the ducting leading to the channel.

The left-hand end of the tunnel is closed pref.- erably airtight :by a .doors. 30, hinged along. its upperiedge, and fitted with a handlew3l. ,Arranged at aconvenient height within the inlet of sthestunnelandprojecting. outside thereof is a Ipair'of;rail's ..32 which forms a'eloading platform and fromz which airamn 33 extends downwardly 1on-imovablebearings extending through each side loitjthej .itunnel; where" the projecting 1 ends. of lithe acting grip,'not shown.

pulley shaft 3'! are under'the control of external tensioning rods 38 fitted atone end with springs 39 by which the wire ropes are tensioned, the springs 38 pressing at one end against a cross bar 49, and at the other against'a' head. 4| on each tensionin'g rod. The endless track is driven by the pulleys 36 at the other end which are mounted one transverse shaft 42 one end of; which is driven by a pulley 43, which in turn is actuated by a chain or other suitable drive tric motor or other prime mover 16.1: 3 r

It is to be noted that the pulley orpulleys 36 at one end of the movingl trackwaye are smaller in diameter than the pulleys 35' at the; other end, so that the upper stretch of the'track has a downa ward slope from'th'e doorway'30 at the mouth of the tunnel, and forms a constantly moving platform to support and progressively. move through the tunnel in-counter direction to the "now of the heated gases, a number of containers 41 which are cylindrical in shape and in which are placed the goods that are to be exposed to the heating treatment. I j

An example of one of the cylindrical containers 41 is shown in perspective in Figure 4. The container is constructed of stout wire mesh with ends E8 and reinforced by metal framing 49.

The circular wall of the container is formed by or includes twosemi circular doors 50, each of which extends halfwayround the'container, and

Figure 4shows one of the doors in a partlyopen position. Each door is hingedat 50a, on one side of the heated gas or gases. j

' A number of such cage-like containers 4'! are rolled upthe ramp 33 on to the loading platform 32 and admitted in 'turn into the open, end of the tunnel'through the door 30 at suitable-intervals. 4 V

Therlcading and the unloading .of the contain- 'ers may alternatively be efiectedrby'a conveyor system such as isdiagranunatically illustrated by way ofexample in Figure 6. This comprises an overhead runway which commences at the outlet .end of'the tunnel l and makes ahalf turn circuit eilon to a return path El and extends through another half-turn at Ela/tofthe inlet end. The runway is provided with any usual form of suspension block and tackle and a quick As a' container 41 shown in dotted lines leaves the tunnel it is carried round the loop 60 onto the return path 6! to a suitable deck 62 at which it and all the containers in turn are unloaded. Fromthis deck the empty containers arepicked "up in turn and moved forward to 'a second deck 63 where they are re-loaded with stock ready to be reclaimed. 'I'hey are then carried on round the loop Ma and lowered onto the loading plat-' form-32 at the tunnel inlet, to await'processing.

fAft'er entering the tunnel, the cQntainers are supported on the jupper stretch of the moving 7' track '34, thefvarious containers being kept separated from one another by crosspins 53jwhi ch make contact with the end rims of the'cont'ainers 4: iilsertedthrough holes 54 in the opposite sides '10 through worm or other gearing ifi from an elecof the tunnel, and two of which are seen in Figure 1. A number of inspection windows such as 55 are provided in theside walls of the tunnel. Due to the moving endless track' each con tainer-is rotated on its own axis and is also allowed to progress intermittently along the tunnel down the slope of the track by temporarily removing the pins 53.

As already stated and as they areicontinuously rotating, the goods 7 contained therein-are thoroughly exposed to the action of the gas;v tainer-sis fitted with'a series of baille plates 56 which slope upwards from the bottom of the tun- The space beneath the connel so that the gas at the bottom is forced upward ,toimpinge'on the containers and thus prevent any tendency for the gas to by-pass the containers.

With the same object'in view, a series of hinged baffle plates 5'! dependfrom thetop of the tunnel each being in such a position that when the con-i tainers come to rest against thepins 53 the baifi-es 57 are immediately over the centre of each container. to the slope of the track.

The, length of the tunnel is preferably such that c the distance between the inlet" door and the gas inlet is, is suificient to progressively treat a number of containers, for example six as shown. In rder to cool'the materials being heated, to

assist in the separation of 'rubber portions from.

' those-of rubberand fabric, and to guard against possible damage by fire, a steam pipe l8a w hich extends across the full widthof the tunnel is positioned at the gas inlet l4 so that the steam impinges on the material when it is atits highest temperature; Iheftunnel-then continues for a further distancetoyprovidea cooling zone-(which maycontain three containers at a time,;for example, and: itijis fitted with a steam pipe [8b Iwhich" is similar to the steam pipe Ilia and which assists inthe cooling. of the heated rubber product, as wellasj preventing danger of fire.' The bottom of. thiszone is formed with a fixed slope indicz-tted at 51a. Finally'thetunnel terminates or steam jet 61,

in a gas lock or discharge compartment 5 8, the

entry into and the exit from which'are' controlled by any suitable type of sliding self-sealing door 59, either manually or mechanically operated.

Such gas lock or discharge compartment .will 7 completely isolate the container .witl'iin' itto allow a further period for cooling. "rWhen-"thezmaterial is'sufticie'ntly cooled the end'door is opened to allow the container to beremoved, the inlet door 59 being at the same time closed. By such an arrangement not only will any unnecessary escape of heat from the tunnel be prevented, but any inrush of atmospheric air orrisk of fire will be prevented by'the isolation of the compartment. Furthento prevent any danger of fire, the compartment as shown is Finally, the general temperature of themain tunnel, as well as that of the cooling zone, may

be controlled by any usual formof thermostatic device or devices, which as being wellknown in many forms it is not herein illustrated.

It should be emphasized that the material being heated in the tunnel device'is under constant inspection and control all the time itis passing through *the tunnel and that the duration or treatment may bevaried by'suitable manipulation V 1 of the pins 53,.

The tunnel as 'describedis made of refractory l 1 v the containers trave1'along the tunnel against the flow of the heating gases These baffle platesvary inlength due 7 fitted with a water spray brick and concrete slabs with or without metallic sheathing and is preferably insulated suffi ciently so that the heat loss of the gases is as low as possible. This is particularly desirable where the gases leaving the tunnel are returned to the main flue before entering an economiser. The tunnel may however be constructed of sheet metal or any other suitable metal which would similarly be efficiently insulated.

It is to be understood that the treatment according to the present invention does not involve any material consumption of power, and that the gases preferably used are readily obtainable inasmuch as they are waste gases and that no high pressures are necessary.

I claim:

1. Apparatus for reclaiming and regenerating waste rubber comprising in combination a tunnel-like casing divided into heated and cooled zones, a discharging compartment at the outer end of the cooled zone, an entrance at the end of the tunnel remote from the cooled zone, means for passing a stream of heated inert exhaust gases through the heated zone from the inner end thereof and toward the entrance end. of the turn nel, an inclined trackway in the bottom of the tunnel throughout the length thereof, at least that portion of the trackway in the heated zone being lovable in a direction longitudinally of the tunnel-like casing, means for moving said track- (I way, a series of cylindrical perforated containers for waste rubber supported on and in rollin contact with the trackway and movable through the tunnel-like casing from the entrance end through the heated and cooled zones and successivel into the discharging compartment, means for isolating the discharging compartment when a container is to be discharged and means for temporarily arresting movement of the containers throu h the tunnel whereby rotary movement is imparted to the containers by engagement with the movable trackway.

2. Apparatus for reclaiming and regenerating waste rubber comprising in combination a tunnel-like casing provided with an entrance and with a discharging compartment, a damper controlled inlet for admitting a stream of heated inert flue exhaust gases at a point medially of the ends of the casing, a controlled outlet for such gases near the entrance end of the tunnel, a trackway on the floor of the tunnel sloping toward the gas inlet and movable in a direction longitudinally of the tunnel-like casing, means for moving the trackway, a series of perforated cylindrical containers for waste rubber supported on and in rolling contact with the trackway and moved by the latter through the tunnel in a direction opposite to the flow of gases, means for intermittently stopping the containers in their travel through the tunnel whereby rotary movement is imparted to the containers by their engagement with the driven trackway.

3. Apparatus as claimed in claim 2 in which the means for intermittently topping the containers in their travel through the tunnel include a plurality of rods adapted to be extended across the tunnel to stop the passage of the containers through the tunnel but allowing them to rotate on their own axes.

4. Apparatus for reclaiming and regenerating waste rubber as claimedin claim '2 wherein a number of upwardly sloping bafile plates are .spaced along the floor of the tunnel and beneath the moving trackway to divert the heated gases upwardly and a number of uniformly spaced transverse bafile plates swingably suspended from the roof of the tunnel for making successive contact with th upper parts of the passing rotating containers to substantially divide the tunnel into compartments and insure of the passage of the gases directly through the rotating containers.

5. Apparatus for reclaiming and regenerating waste rubber comprising in combination a tunthe casing, means for moving the trackway, a correspondingly inclined floor in the cooling zone, a series of removable perforated cylindrical containers supported transversely on and in rolling contact with movable trackway and inclined floor for receiving the waste rubber in finely divided pieces, said inclined floor acting to rotate the containers as they pass down the floor, and means for temporarily retaining the containers in set positions within the desired portions of the casing for a predetermined period of time, and the movable trackway in the heated zone acting to insure rotation of the containers about their own axes due to the rolling contact of the container therewith,

6. Apparatus for reclaiming and regenerating waste rubber as claimed in claim 5 wherein a series of uniformly spaced transverse baffle plates depend from the top of the casing to divide the heated zone into a plurality of compartments, said baffle plates terminating at the uppermost surface of the containers so that the fiue gases are compelled to pass through the containers and a series of upwardly inclined baffles co-opcrating with the partition and rising from the floor of the casing to the under surface of the movable trackway to insure the passage of the gases from one compartment to the other only through the containers.

7. Apparatus for reclaiming and regenerating waste rubber comprising a combination with a tunnel as claimed in claim 2 of an external runway extending irom the discharging end of the tunnel then curved and extended in parallel relation to the tunnel and finally curved and extended back to the entrance end of the tunnel in such a manner that the'runway and tunnel form a substantial loop, a loading and unloading dock at about the center of the runway opposite the tunnel so that each container with the finished goods may be moved from the tunnel around the runway and. unloaded and then refilled with stock to be treated and then moved around to the tunnel inlet.

8. Apparatus as claimed in claim 2 in which each of the cylindrical containers comprises end plates and sides of open mesh work having internal partitions of open mesh work forming a number of compartments therein and portions of the sides being in the form of hinged doors by which waste rubber may be passed into or withdrawn from the compartments.

ALEXANDER JOHNSTON. 

